Printing-plate.



S. E. DITTMAN.

PRINTING PLATE.

APPLICATION FILED AUG. 2s, 191s.

Patented Feb. 16, 1915.

SAMUEL DITTMAN, 0F NEW `gORK, TY.

PRINTING-PLATE.

Specification of Letters Patent.

Patented Feb. 16, 1915.

Application med august 2s, 1913. serial No. 787,1`i4.

To all 'whom it may concern Be it known that I, SAMUEL E. DITTMAN, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Printing-Plates; and I do hereby declare that the following is a'full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to a novel means applicable for use in the process or method of reproducing pictures in their original or natural colors, and especially a method of coloring black and white reproductions of pen and ink sketches, wash drawings, oil paintings, photographs, or any subject calling for the use of a color or colors.

In carrying out my novel method for printing in several colors only one printing plate, that is to say, an original half-tone or other relief plate, herein referred to as the image or key-plate, is employed for making a print or impression in black or any 'other color. For making other color impressions a relief plate having uniformly disposed, minute elevations or points, adapted for printing a iat tint when inked and applied to the paper with uniform pressure, is employed in connection with an overlay or overlays, prepared from the key-plate, and adapted to give an impression or impressionsfrom the flat tint relief plate, corresponding with the form Vand thickness of the parts of the overlay or overlays The said image or key-plate is prepared in the usual manner, to those skilled in the art. For making such overlay a print or proof is taken from the key-plate on a sheet -of paper or like thin, iiexible material. The several printed impressions are used in the preparation of a series of overlays, one for each of the diierent colors to be employed. ,Such overlays maybe prepared by any of the processes heretofore used in making overlays, such manner that the areas of the impressions on the overlay sheet, which are' to be in a color, are so treated that the said sheet in such areas is made thicker than other parts of the sheet the increased thickness varying on 'dierent' parts of the overlay sheet according to the depth of tone desired. As for instance, this result may be accomplished according to a process heretofore employed for making overlays by the use of prints or proofs taken from an image'or key-plate, the same consisting in applying ink or some adhesive material tothe areas of the impression in which the color i'sto be printed, and then applying to the sheet While the ink or adhesive materialfis still in a sticky condition, a powdered material, which is caused to adhere in a greater quantity or 'thickness to the parts of the impression'to be printed in Idarker shade, and in a less quantity or thickness to the parts to be printed in lighter shade, so that the sheet s o treated has an added thickness o f pulverized material irnparted to it, varying according to the depth of shade ofthe color to be printed by the use of the overlay. 'The overla may also be prepared in other ways, as` or instance, it may be a chalk" overlay, or a cut paper overlay.

For 'the purposes of illustration, l will describe my novel device asv applied vin a process used for printing in the three primary colors, namely, red, yellow and blue. Each color is printed by a separate impression and by the use of an overlay prepared for that color, as above described, in connection with a half-tone granular or similar at tint relief plate; the surface-structure of said plate being similar to that of the half-tone relief printing plates used in the art, but having uniformly distributed' printing points or elevations, so that it ve an impression, uniform in depth or sha Le,'1 1nder uniform pressure. The overlay, made of varying thickness in its different parts, in` accordance with the desired color areas and depth oftone to be given to the different parts of such color areas, is applied in the usual manner to the tympan Sheet of the press. Y When the sheet to be printed is pressedV against the inked surface of theiiat-tint plate, the areas of the paper correspondinrwith the thickest parts of the overlay are, t ough theaction of said overlay Subject to the greatest'pressure between the tympan and the `fat-ti' 'n t relief plate, and .therefore receive asti-on" 0X' heavy impression, while the 'areas o the paper corresponding to the untliickend or thinner parts o f the overlay sheet receive no impression from the inked plate, or are subject to a li ht ressure giving a proportionally light ignk iinpression. For printing 1n several colors the printing operation is repeated by the use of-each color overlay, the,

' invention to the use of the key-plate itself usual process of photo-engravmg.

in this printing operation, nor to any definite number of color impressions to be thus superposed. Nor do I limit myself to the order in which the color impressions and the key-plate impressions are printed, as the order of making the impresslons may be reversed or` interchanged without affecting the results obtained.

The features of my invention 'may be better understood by reference to the accom- Vpanying drawings, in which:

Figure 1 shows the impression (from a key or image printing plate, adapted for printing an entire picture in black or a singlel color; Fig. 2 shows an overlay sheet containing an impression from the key-plate; Fig. 3' is a face view of the overlay sheet, as prepared for printing one color; Fig. 3 shows the overlay in section, taken on line 3"-3a of Fi g. 3; Fi 4 shows in plan view a fiat-tint half-tone point or dot surface plate, with a portion thereof greatly magnified; Fig. 5 is a sectional view of a halftone point or dot surface greatly magnified; Fig. 6 is a plan view of a granular flat-tint surface with a portion thereof greatlv magnified; Fig. 7 is a sectional view of a halftone dot surface, with alternating high and low points, greatly magnified; Fig. 8 illustrates the tone-effects produced in printing with varying pressure on a half-tone dot surface, having alternating high and low points, greatly magnified.

e impression A (Fig. 1) is such as may be printed from a half-tone or other relief plate (not shown) prepared by the e area. marked` a in said impression A represents a part or area of the picture which is to receive an additional impression in one color.

Figs. 2 and 3 illustrate the method of making the color-overlay sheet. Fig. 2 shows the overlay sheet B after it has received an impression from the key-plate, andr Fig.`.3 shows the same after the application thereto of adhesive material and powdered substance, to increase the thickness of the sheet, in the area b, intended to be printed in a single color and corresponding with the area a in Fig. 1. Fig. 3* shows the same overlay sheet in Section, after the pulverized material has been applied thereto,so as to increase Vthe thickness of the sheet, in the area b corresponding with the area a of the key-plate impression. It will bev understood that 'several overlay sheets prepared as described, and arranged in superposed relation, so as to form several layers and to give additional thickness at the thickened parts, may be used as the overlay in the making of eithetl impression in the printing operation.

Figs. et to 7 illustrate -various surface structures of flat tint relief plates adapted for use in carrying out my process. Figs. 4 and 5 show the ordinary half-tone dot surface, C, magnified, consisting of minute, tapered or pyramidal projections c, called points or dots, of uniform height and placed vuniformly equidistant in intersecting rows. Such surfaces have usually from 175 to 200 points or dots to the linear inch. Fig. 6' illustrates the magnified surface of a grans ular fiat-tint plate, having a uniformly roughened surface of irregular elevation and depression corresponding approximately in Fig.`

fineness to the 20D-dot half-tone plate. 7 shows a surface with alternating high points d and low points e, such as would correspond to a 10U-'dot surface when printing only the high points Z and a 20G-dot surface-when printing both the high points d and low points e.

The high and low dot flat-tint plate above described is particularly adapted to be used in my process, as it gives a :wide range of gradation in shade or depths of color withl but slight variation' of pressure.. Fig. 8

Villustrates a few of the gradations, in magnified proportions, of the impression received from such high-and-low dot surface, varying in degree of depth of color in pro- D Ortion tothe pressure given to the overlay. F shoyvs the result of printing with such light pressure that the points d only of the 'sheet come in contact with corresponding dots d of the printing surface; G shows the effect ofv printing with suicient pressure to depress the paper into contact wlth the alternate low dots e, producing the light dots ealternating with the heavier dots d.

H shows the effect o f printing with suicient pressure to produce a nearly solid tone or color; and J shows the effect obtained by printing with sulicientpressure to produce a solid color.l To produce the best results I have found it preferable to provide a specially prepared'flat-tint plate of such suitable depth that the paper may easily reach bottom for solid color. In other words, in such a specially prepared plate the projections c (Fig. 5) ord and e (Fig. 7) are made relatively 10W, andthe depressed portions `therebetween shallow, so that it does not require excessive pressure on the paper to. produce a solid color impression thereupon. There is no limit, however, to the variety of such fiat-tint surfaces which are adaptable to my process without deviating from the fundamental principles of my in- In printing a picture or the like by the' use of the image or key-plate and a plurality of overlays, the color-impressions are made to register with the impression from the key-plate. Each color impression is made by inking the flat-tint plate and pressing the paper against said plate through the action of the overlay, so that the impression will correspond with the overlay both as to location of the color areas and the shading of the same. When pressure is applied to the sheet to be printed, with the overlay held in position between the tympan and the Hat-tint plate, it is evident that the presence of the added thickness in the area b of the overlay produces such pressure in the thickened area of said sheet as is necessary for making the color impression. j

In printing with the overlay as described, the printing paper mayreceive a colored ink impression from some parts of the flat-tint plate and no impression from other` parts of such plate, or it may receive an impression varying in depth or shade in its different parts according to the thickness of the corresponding parts of the overlay. The impression from the original key-plate, or duplicate of the same, will usually be made in black or dark ink and will show in outline or otherwise the entire subject shown by the picture, while the completed print will have all of the desired colors localized and shaded as desired.

My device herein described may be further extended to be used in connection with any of the present methods of color-printing for the additional building up of areas which may be light in a print from the keyplate, but which it is desired to make heavier in the case of one or more of the additional colors. The at-tintplate is neutral for any subject, and can be inked in any color, so it may be used with any number of separate overlays, made from a key-plate not exceeding the same in size, until it is worn out.

I claim as my invention:

l. In the art of printing, means for producing impressions, comprising a printing surface provided with a plurality of series of points or projections differing in height and each consisting of points or projections of the same height, which are uniformly arranged with respect to each other; the points constituting the several series being uniformly distributed in interspersed relation to each other.

2. In the art of printing, means for producing impressions, comprising a printing surface provided with high and low points or projections alternately arranged and spaced equidistantly apart, said plate being adapted to produce a variation of dot impressions by the variation of pressure upon the material receiving the impression.

3. In the art of printing, means for producing impressions, comprising a plate having a printing surface provided with uniformly and alternately arranged high and low points or projections in which the depressions between said points or projections are relatively shallow, said plate being adapted to produce a variation of dot impressions varying in depth from faint to .solid by relatively slight variations of pressure upon the material receiving the impression.

4. In the art of printing, means for proy ducing impressions, comprising a fiat tint relief plate having a printing surface provided with high and low points or projections spaced equidistantly apart and arranged in intersecting rows, said plate being adapted to.produce a wide variation of impressions with a slight variation of pressure upon the material receiving the impression. l

In testimony, that I, claim the foregoing as my invention I affix my signature in the presence of two witnesses.

SAMUEL E. DITTMAN.

Witnesses:

MATILDA E. ErrNnR, ELwooD W. BAKER. 

